40555217921 has 2 divisors, whose sum is σ = 40555217922. Its totient is φ = 40555217920.

The previous prime is 40555217917. The next prime is 40555217999. The reversal of 40555217921 is 12971255504.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 32296043521 + 8259174400 = 179711^2 + 90880^2 .

It is a cyclic number.

It is not a de Polignac number, because 40555217921 - 2² = 40555217917 is a prime.

It is not a weakly prime, because it can be changed into another prime (40555217621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 20277608960 + 20277608961.

It is an arithmetic number, because the mean of its divisors is an integer number (20277608961).

Almost surely, 2^40555217921 is an apocalyptic number.

It is an amenable number.

40555217921 is a deficient number, since it is larger than the sum of its proper divisors (1).

40555217921 is an equidigital number, since it uses as much as digits as its factorization.

40555217921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 126000, while the sum is 41.

The spelling of 40555217921 in words is "forty billion, five hundred fifty-five million, two hundred seventeen thousand, nine hundred twenty-one".